Practise deliberately to learn a skill

No matter how much you prepare and learn about a new skill, at some point you have to start doing it.
It is not enough to practise and put in the time, the practise must be deliberately focussed on learning a new skill

Effective practise need to be self-test rather than mindless review
study in 2008 by Jeffrey Karpicke of Purdue University, group of students were given vocab words to learn. Students who used active recall remembered 80% of the new words versus 34% for those who only passively reviewed the words.
Practise is hard. if its not, you are not doing it right
Aggressive review: study problematic areas deliberately and repetitively, test your understanding
For example when learning a new instrument/song focus on the problem area instead of the teh whole song. once it is learned move on to another area
As an example: 2 basketball players practise for one hour. One has a second player retrieving the ball for him, and a colleague tracking the lcoation of each shot, after 10min he reviews where his weakness is and focuses on that specific area. the second merely shoots throws randomly for one hour, retrieving the ball himself. even thouth he is also improving, player 1 will improve at a much faster rate

The Science of Rapid Skill Acquisition: Advanced Methods to Learn, Remember, and Master New Skills, Information, and Abilities - Peter Hollins
James Clear

“Consider the activity of two basketball players practicing free throws for one hour. Player A shoots 200 practice shots, Player B shoots 50. The Player B retrieves his own shots, dribbles leisurely and takes several breaks to talk to friends. Player A has a colleague who retrieves the ball after each attempt. The colleague keeps a record of shots made. If the shot is missed the colleague records whether the miss was short, long, left or right and the shooter reviews the results after every 10 minutes of practice. To characterize their hour of practice as equal would hardly be accurate. Assuming this is typical of their practice routine and they are equally skilled at the start, which would you predict would be the better shooter after only 100 hours of practice?”

_—_Aubrey Daniels